1. Technical Field
This invention generally relates to trailerable engine housings having reduced noise characteristics, and more specifically to trailerable engine housings of unibody construction with cross flow ventilation through vents which obstruct or impede transmission of sound.
2. Background
Trailerable engine housings are used as power sources at remote locations. Gas or diesel engines are usually mounted upon a trailer frame, together with their accessory units such as cooling or radiator systems, fuel tanks, and associated electrical systems, and are used to drive a power source, such as, for example, an electrical generator, hydraulic pump, air compressor, or water pump. They are most commonly used in civil construction applications such as road or building construction projects where regular utility services may not be readily available. Examples of such applications include trailerable light towers used for illumination of road construction projects where connection to electrical power lines would be difficult or impossible to achieve. Another example would be the use of a trailerable engine housing as a source of compressed air for a pneumatic jack hammer. This list of different applications would be practically endless, and no attempt will be made to provide a complete list. But at a minimum it would include the power sources enumerated above.
They all have one thing in common. They all have a noise and heat emitting engine, usually gas or diesel fueled.
The typical prior art trailerable engine housing includes a frame defining a platform which is supported by a sprung single axle, and a trailer hitch or tongue assembly. The engine and the driven power source, together with their associated systems, are mounted atop the frame, and in most cases, some sort of a cowling is provided for weather and mechanical and electrical system protection.
The gas or diesel engines may be either water cooled, in which case a radiator, with air flow across it, must be provided, or air cooled, heat exchanging cooling fins must be provided with a constant source of cooling air flow. As a result, the prior art cowlings are designed to be well ventilated, so as to provide adequate air flow to keep the engine, and for that matter, the power source which also generates heat, cooled to within the designed operating temperature range.
These engines, and for that matter the attached power source, also generate noise. If the noise is loud enough it becomes an environmental hazard for a number of different reasons. The engine noise may impede communications between workers, and it may become an annoying distraction, since listening to a roaring engine over an eight to twelve hour work day may become quite annoying and even medically harmful. Reducing the operating noise level requires substantial sound baffling, the provision of which would conflict with the need for a well ventilated engine housing. If one were to design a sound reducing engine housing which encases the engine to reduce emitted noise levels, the engine will overheat since air flow will be reduced.
In addition to the conflicting design criteria between ventilating air flow and noise reduction, there is a third problem with the prior art trailerable engine housing. It is the construction technique used in the prior art, namely use of the conventional platform trailer frame atop of which everything else is set. Like the antiquated automobile construction techniques of old, where a separate vehicle frame was provided and to which everything else was bolted, welded or otherwise attached, the prior art trailerable engine housing has a high profile and a high center of gravity. This causes problems with trailer stability, both during transport, and perhaps just as importantly, when the trailerable engine housing serves as the weighted base for a light tower, or anything else that extends upward and is exposed to the wind, and thus subject to being blown over in the wind.
Accordingly what is needed is a trailerable engine housing that is stable, provides a lowered center of gravity, and is constructed in such a manner to provide both adequate cooling air flow and noise reduction.